Solid electrolytic capacitors (e.g., tantalum capacitors) are typically made by pressing a metal powder (e.g., tantalum) around a metal lead wire, sintering the pressed part, anodizing the sintered anode, and thereafter applying a solid electrolyte. Intrinsically conductive polymers are often employed as the solid electrolyte due to their advantageous low equivalent series resistance (“ESR”) and “non-burning/non-ignition” failure mode. Such electrolytes can be formed through in situ chemical polymerization of the monomer in the presence of a catalyst and dopant. One of the problems with conventional capacitors that employ in situ polymerized polymers is that they tend to fail at high voltages, such as experienced during a fast switch on or operational current spike. In an attempt to overcome some of these issues, premade conductive polymer slurries have also been employed in certain applications as an alternative solid electrolyte material. While some benefits have been achieved with these capacitors in high voltage environments, problems nevertheless remain. For instance, one problem with polymer slurry-based capacitors is that it is often difficult for the interior polymer layers, whether in situ polymerized or made from a polymer slurry, to penetrate and uniformly coat the pores of the anode. Not only does this reduce the points of contact between the electrolyte and dielectric, but it can also cause delamination of the polymer from the dielectric during mounting or use. As a result of these problems, it is often difficult to achieve ultralow ESR and/or leakage current values, particularly at relatively high voltages.
As such, a need currently exists for an improved electrolytic capacitor containing a conductive polymer solid electrolyte.